How to find the C=corresponding x axis values of a peak on Y-axis?

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I have to find the 'x' values at which the peak is maximum. How can I find that? Please help.
x=[11500.2 11477.9 11417.3 11426.4 11413 11382.9 11375.1 11347.9 11351.1 11329.3 11318.9 11343.4 11360.7 11378.4 11414.2 11408.2 11413.6 11449.4 11444.1 11421.4 11388.5 11429.3 11438.1 11432.9 11408.2 11434.3 11444.8 11443.5 11491.8 11503.8 11581.8 11525.9 11529.5 11557.6 11523 11516 11504.1 11492.9 11480.3 11495.9 11445.1 11437.7 11468.5 11463 11488.5 11470.3 11491.1 11480.2 11488.9 11453.8 11456 11434.5 11460.6 11456.1 11454 11468.3 11464.4 11501 11453.8 11474.2 11458.2 11452.8 11434.6 11447.3 11379.5 11396.4 11409.9 11405.6 11433.3 11435.6 11434.2 11415.5 11483.6 11434.6 11452.2 11471.5 11445 11462.6 11433.3 11440.2 11442.3 11456 11408.6 11399.7 11369.8 11372.6 11401.4 11405 11426.6 11430.3 11405.6 11409.8 11405 11399.7 11381.2 11392.5 11383.6 11365.8 11362.4 11347.8 ...
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11365.9 11366.6 11369.4 11386.2 11405.7 11349 11372.3 11370.5 11370.2 11402.6 11385 11401.8 11382.5 11362.5 11353.6 11368.9 11365.3 11377.3 11375.3 11385.2 11364.7 11357 11366.8 11337.1 11348.1 11316.3 11308.3 11322.2 11311 11341.8 11350.1 11340.1 11348.3 11338.4 11379.9 11395.1 11368.1 11363.4 11342.3 11329.5 11317.9 11318.7 11304.5 11256.4 11277.6 11247.3 11264.2 11247.9 11245.6 11243.5 11257.1 11289.5 11250.5 11252.9 11243.2 11278.9 11323.5 11299.4 11328.1 11306.9 11311.5 11317.8 11308.3 11302.3 11276.2 11295.2 11252.7 11267.4 11268.3 11265.8 11271.8 11266.6 11280.2 11273.3 11300.6 11280.5 11298.7 11341.9 11336.2 11354.5 11351 11344.7 11346.5 11321.8 11358.6 11340.5 11352.6 11333.3 11347.1 11369.5 11352.9 11359.9 11335.2 11308.9 11331.4 11319.5 11344.5 11337.1 11352.8 11371.9 ...
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11306.7 11320.4 11350.3 11314.6 11356.8 11356.7 11398.8 11377.8 11368 11365.7 11357.6 11368.1 11362.3 11385.3 11380.3 11398.1 11368.4 11390.9 11410.7 11371.2 11386.2 11375.6 11370.2 11401.5 11394.5 11388.7 11370.1 11391.7 11399.6 11393.8 11398.6 11417.7 11413.5 11397 11432.9 11415.3 11423.2 11402.4 11399.1 11402.7 11390.5 11421.6 11378.3 11409.1 11408.5 11408.3 11442.2 11410.2 11449.1 11428.1 11444.5 11461.2 11437.1 11380 11384.3 11380.8 11356.6 11371.3 11360.7 11384.6 11389.7 11364.9 11370.7 11354 11356.8 11380.4 11371.1 11396.3 11370 11392.6 11369.9 11382.5 11372.3 11359.6 11335 11324.7 11337.8 11338.7 11345 11321.7 11350.4 11345.6 11366.6 11346 11325 11331.1 11336.8 11337.5 11323.5 11337.6 11310.2 11316.2 11367.4 11346.4 11372 11379.5 11389.3 11374.4 11372.5 11371.7 ...
11356 11354.2 11335.5 11372.6 11370.7 11386.8 11363.4 11358.3 11397.9 11383.7 11396.8 11397.8 11385.2 11401.2 11395.9 11398.1 11394 11399.5 11373.6 11388.2 11377.5 11394.6 11414 11393.3 11406.4 11405.6 11410.5 11434.6 11413.3 11453.9 11439.2 11457.6 11458.4 11446.7 11439.1 11433.6 11441.8 11414.7 11436.4 11403.5 11450.9 11432.5 11439.6 11473.3 11449.6 11463.1 11452.3 11427.2 11401.4 11405.6 11360.7 11366.5 11336.1 11317.6 11289.2 11306.6 11306.7 11302.1 11350.6 11343.2 11368.7 11370 11365.4 11334.1 11317.6 11336 11305.5 11330.4 11306.5 11317.9 11321.9 11313.5 11344.5 11307.2 11335.5 11316.7 11334.7 11313.4 11326.3 11313.2 11307.2 11334.8 11321 11323.6 11317.9 11338.3 11330.7 11314.4 11334.7 11335.3 11353.3 11341.7 11366.5 11351.7 11353.6 11364.3 11361 11351.9 11337.9 11372.8];
Fx = fft(x - mean(x));
plot(abs(Fx(1:10)))
  4 个评论
Chunru
Chunru 2021-7-14
You asked the question. People answered it in details. You asked again and said people don't understand your question. Please respect the people spending effort to help you.
Can I assume you are the same person posting the following question?
Haya Ali
Haya Ali 2021-7-14
编辑:Haya Ali 2021-7-14
Hi Chunru, Maybe i was unable to explain my question in a right way. Thank you for your help in the previous post. I was confused because i was getting the wrong answer suing that code but when I replaced
idx = idx + (10-1);
by
idx = idx + r(1) - 1; % as suggested by walter
the answer is right.
Thanks again.

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采纳的回答

Steven Lord
Steven Lord 2021-7-13
Index into the x vector using the output of islocalmax.
x = 1:100;
A = (1-cos(2*pi*0.01*x)).*sin(2*pi*0.15*x);
tf = islocalmax(A);
plot(x, A, 'k-+');
hold on
plot(x(tf), A(tf), 'go', 'MarkerSize', 8, 'MarkerFaceColor', 'g')

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